Worst Enemy
by suicidalunicorn97
Summary: Team Free Will chases down a cursed object that causes whoever touches it to kill the person they hate the most. Unfortunately for Dean, that person is himself. Trigger warning for Suicidal thoughts, suicide attempt. Set in Season 8 after Cas gets out of Purgatory and decides to start hunting with Sam and Dean.
1. Chapter 1

From the moment Castiel had decided to be a hunter, cases were easier to find, and easier to take care of. Dean had to admit that working with an angel had its perks. They seemed to be helping people at a record pace. What Cas lacked in experience, he made up for with enthusiasm. The angel was slowly becoming a better hunter, and also improving his 'people skills'. Dean couldn't help but feel proud of his friend.

"I've found another case." Cas appeared in the middle of the motel room, not bothering to start with a greeting.

"Already?" Sam asked incredulously. "We just wrapped up the last one."

"Yes. This one is only a two hour drive. Although, time wouldn't be an issue if you would let me-"

"Zap us everywhere? No thanks." Dean sighed. "Dude, we gotta slow down or we'll burn out. You do realize that we need sleep, right?"

"Right...I'm sorry." Cas looked down sheepishly.

"It's okay, just give us a few hours. Why don't you go check on Kevin, see how he's doing with the Demon Tablet?"

"Of course."

* * *

The next morning, Dean awoke to a shadow standing over his bed. The adrenaline quickly overcame his sleepiness, and he instinctively reached for the gun under his pillow.

"It's just me." Cas spoke, sounding amused.

"Dammit, Cas." Dean grumbled. "I could have shot you."

"Even if you had managed it, you know bullets can't harm me."

"Still."

At this point, Sam was awake too. He ran a hand through his shaggy hair, and Dean resisted the urge to call his brother a hippie and tell him to get a haircut.

* * *

They were on the road within an hour. While they were driving, Cas filled them in.

"The town has had four homicides in the last week."

"Let me guess-no leads?"

"Actually, they caught the killer in every case. One man killed the boy who got his daughter pregnant. A wife murdered her cheating husband's lover. A businessman shot his coworker who got a promotion instead of him. And the last one, a 13 year old boy killed the bully who'd been tormenting him for months."

"Are you sure this is our kind of thing? Those all sound like typical motives for murder."

"Yeah, but four in a week? That's way above average for a town this size." Sam pointed out.

"Sam is right. Besides, there is something unnatural involved, I can feel its energy." Cas said.

"Alright, well can you get to the source of that 'energy'?"

"I could feel it on each of the killers, but I don't know where it's coming from or what it is." Cas said apologetically.

"That's okay. We'll do what we do best, and get to the bottom of this."

* * *

They interviewed all four killers, and got a surprisingly similar answer from each of them. They'd all been thinking about committing the murder, but never actually intended to act on those thoughts. They simply woke up that morning, and decided that these people did in fact need to die. After the act, they were suddenly overcome by guilt and shock, and had turned themselves in.

After discussing multiple theories, their best lead seemed to be a cursed object. Now they just needed to figure out where all the victims/murderers had come in contact with it.

It wasn't easy, but they finally found a lead. They talked to the friends and family of the victims turned killers, and discovered that all of them had attended a yard sale a few blocks away. Unfortunately, none of them knew what they'd bought there.

Naturally, they went to check it out. They stood outside the sketchy looking house and wondered how the guy had gotten anyone to come for a yard sale. It looked like a crack house.

"Don't touch anything until we determine what the cursed object is." Cas reminded them.

"Uh, yeah. Wasn't planning on it." Sam said.

"You know, we're already trying to kill the people we want dead. Maybe it'd give us a run of luck and help us actually find that son of a bitch Crowley." Dean muttered.

Just then, a short man answered the door, looking as if he'd just woken up. He was in his early forties, and morbidly obese. "Can I help you?"

"Yes. We need to search your house." Cas stated simply.

Dean sighed. Cas could definitely work on a couple things.

"What? Why? What's going on?" The man demanded to know, alarmed.

"I think you know." Cas squinted at him, and the man gulped.

"Listen, I told Marco I'd pay him back..."

"Cas, he doesn't know." Sam realized.

"Know what?"

"Could we come in for a minute?"

The inside of the house was worse than the outside, with empty beer cans and other trash strewn around. "Sorry about the mess." The man apologized. "I'm Hector. And you are?"

"No one of import."

 _Geez, Cas...he's gonna think we're the mafia or something._ Dean thought. They had originally planned to let Cas do all the talking so he could practice, but it was clear that Hector was getting suspicious.

"We're from the FBI." Dean forced a smile. "Now, we need to know exactly what you sold at the yard sale you hosted a few days ago."

"The FBI? Why is the Federal Government interested in my yard sale?"

"Please just answer the question."

"Okay...umm, my grandma passed away about a month ago, and I needed money. I was selling her stuff. I sold some furniture, jewelry, and her old coin collection. I think they were Ancient Greek or something. I sold them to like four different people."

"The coins...do you have any left?" Cas frowned.

"No. There were only four. What's this about?"

"Did they come in a red and gold box?"

"Yeah, how did you know?" Hector was looking at Cas as if he had a third eye.

"It's not the first time I've encountered these. There used to be twelve of them, but some were lost over the years. I always wondered what happened to the remaining four. We need that box."

"How much will you give me for it?" The man asked hopefully.

Dean reached into his pocket to see how much cash he had, but Cas had other ideas. He grabbed Hector by the front of his shirt and pushed him up against the wall. "We are the Government. We take what we need, and you will give it to us."

"Actually that's not how the Constitution works-"

"NOW." Cas growled.

"Yikes, okay, okay..." Hector scrambled off to find it.

"You could have been a little more gentle with the guy, Cas." Sam glared.

"These coins are nothing to fool around with. They've been around for centuries, causing murderous rage in those who touch them. They cause the person to immediately begin planning the demise of the person they hate the most."

"Still. The poor bastard doesn't know what he's gotten into."

Cas ignored this comment, and took the empty box from Hector's hands once he returned. Dean felt bad for the guy, and slipped him a $50 bill on the way out.

Now to find the coins.

* * *

They assumed the coins would be locked up in Evidence, so they went to the station. Cas made their lives easy, and simply popped into the Evidence room to take the them. He returned within minutes, all four coins safely tucked away in the box.

Back at the motel room, Dean couldn't stop thinking about his earlier idea. All the murderers had succeeded in killing the person they hated the most. What if this was their break? What if the coins would help them catch Crowley and finish the bastard?

He knew Cas would never consent to him trying, so he came up with a plan.

"Hey, Cas."

"Yes, Dean?" The angel stared at him curiously.

"Could you go check on Kevin? I have a bad feeling about him. I just wanna make sure everything is okay."

Cas frowned. "Of course." In an instant, he was gone.

Sam was taking the first shower, so Dean was all alone with the coins. He quickly opened the box and took one of them out. He held it in his hand, feeling the weight of the ancient bronze. It was heavy for something so small, and it was remarkably well-preserved for being thousands of years old.

At first, he didn't think it was working. He attributed this to the fact that they were already trying to kill Crowley. He was about to put the coin back in the box, when it hit him.

 _You know who you hate the most._

Just like that, he realized that it wasn't Crowley.

It was himself.


	2. Chapter 2

**Trigger warning for suicide attempt, and detailed description of drugs used to commit suicide.**

* * *

For a long time now, Dean had felt like he was living on borrowed time. He should have died a long time ago. The first time, when he messed up his heart and Sam had found that faith healer. The next time, after the car accident, when their father had given his soul to save Dean's life. And again when he went to Hell, and Castiel rescued him. There were a lot of close calls between now and then, and Dean was beginning to wonder if he even _could_ die.

He'd come close to testing that theory before. After losing Sam the first time, he almost put a gun to his head. But he figured he would at least try to save his brother. And it had worked.

Thoughts of suicide weren't a new thing. He'd considered it a lot, especially after getting out of Hell. The guilt of torturing so many souls...he needed to atone for it somehow.

After Sam had jumped Lucifer into the pit, Dean was going to end it. He was just _done._ He needed this nightmare to end, he couldn't take it anymore. He had every intention of driving Baby off a cliff. But on the way, he had stopped to say goodbye to Lisa and Ben. They convinced him to stay, and they saved his life.

Sam came back, life went on. But there was always this thought in the back of Dean's mind...that he shouldn't be here. Some days were worse than others, but he kept going. For Sammy.

But tonight...tonight he just couldn't. Self-loathing was consuming him. Guilt. How many times he'd let Sammy down. His father. Jo. Ellen. Bobby. Basically everyone he cared about.

He realized he was standing in the middle of the room, still clutching the coin in his hand. He unconsciously slipped it into his pocket, and drew a shaky breath. He needed some air. It felt like his brain was in a fog, with only one small light to guide him. One thing he was hyper-focused on. He knew what he needed to do.

There were a lot of ways he could go, but he didn't want to leave a mess for Sam to clean up. A headshot would be the quickest way to go, but it was an unpleasant scene to walk into. He didn't want Sam to see his brains all over the wall.

 _Pills._

He quickly left the motel, not even leaving Sam a note. He would be back soon.

He drove to the pharmacy, which of course was closed this time of night. It wasn't hard to break in, he simply picked the lock and disabled the security cameras. Not that he needed to; after tonight it wouldn't matter. He almost laughed at how easy this was. Too easy. Almost like luck was on his side.

This wasn't the first time he'd planned this. He knew exactly which drugs would do the trick. He hopped behind the pharmacist's counter and quickly located the Phenobarbital, along with Propranolol. He was about to leave when he spotted a Pediatric Electrolyte drink, which prevents vomiting. He could use that to make sure the pills didn't come back up.

Dean was in and out of the place within ten minutes. He drove back to the motel and parked, but didn't go in. Sam was probably out of the shower by now, and wondering where he was. If he was gonna do this, it had to be here.

He popped the top off the barbiturates, and took a handful. He didn't even hesitate before washing them down with the Electrolyte drink. He repeated the process until the bottle was gone, easily 60 pills. Now for the Phenobarbital. He did the same with these, starting to feel a little woozy. He finished off the drink, and leaned back against the impala's seat.

He could _feel_ the barbiturate/beta-blocker cocktail slowing his heart and closing his airway. It wouldn't be long now. As his chest continued to tighten, he realized that he didn't want to die alone.

"Sammy." He whispered. He hadn't even told his brother goodbye. He hadn't written a note. What if Sam tried to bring him back? He had to understand that this was Dean's choice.

With difficulty, he stepped out of the Impala, leaning up against it for support. He staggered to the door and knocked. "Let me in, Sammy." He slurred.

The door opened, and Sam stood there, looking worried and kind of pissed. "Dude, if you were gonna go get drunk, you should have at least left a note."

"Sorry."

"What did you drink? You couldn't have been gone more than 20 minutes, I've never seen you get drunk this fast." Sam was staring at him.

Dean's vision was getting blurry. He pushed his way past Sam, and didn't even make it to the bed before collapsing onto the floor.

"Dean!" Sam dropped to his knees beside his brother. "Dean, what happened? Were you drugged?"

"Sammy...'m sorry. Please...don't leave me." Dean reached out for Sam. God, it hurt so bad...

"I'm not leaving," Sam was in a panic. "CAS!" He cried out.

"No." Dean tried to say. "Let me die," but he started seizing. His body felt like it was on fire. He couldn't breathe. It felt like his heart was trying to pump glue through his veins. He was shaking. It felt like he was being struck by lightning.

He could vaguely hear Sam screaming out for Castiel. _Shit._ If Cas got here in time...

He never finished the thought. Just when he couldn't take the pain anymore, he blacked out, praying this was the end.

* * *

 **Note to my readers: Please call a suicide hotline, or reach out to someone else if you are experiencing suicidal thoughts.**


	3. Chapter 3

Castiel had arrived to find Kevin intact, if not a little discouraged. He hadn't made much progress in translating the Demon Tablet. The young prophet was lonely, so Cas had stayed with him a while. They were just finishing a conversation about the nutritional value of papaya when Cas heard Sam praying. It was more of a scream than a prayer, and it caught his attention immediately.

The angel quickly said goodbye to Kevin, and rushed back to the motel. He appeared in the middle of the room, and instantly felt the emotional chaos. Dean was thrashing around on the floor, in the throes of a seizure. There was a dark, dark energy surrounding him. Sam was trying to hold him down so he didn't hurt himself. The younger Winchester was hyperventilating, and crying out for Cas.

The angel knelt beside Dean and touched his hand. He could feel poison rushing through his body, the effect of barbiturates and beta-blockers if he wasn't mistaken. Along with the physical venom, he also felt something darker. Something toxic in Dean's mind...in his _soul._ Complete and utter despair. Intense self-hatred. Misery. Desolation. Anguish. Hopelessness. Guilt. _Agony._

It was then that Cas realized what had happened.

With a single touch, the angel removed the drugs from Dean's system. He stopped seizing, and lie motionless on the floor. Sam was breathing hard, and shaking. He was obviously having a panic attack. Cas put a comforting hand on his shoulder. "Dean is alright now. Let's get him onto the bed." Together they lifted Dean and laid him down gently on the mattress.

"What the hell happened?" Sam asked with wide eyes.

Cas reached into Dean's pocket and pulled out one of the cursed coins, using his trenchcoat as a glove. He didn't know if they affected angels, but he didn't want to take that chance. He carefully placed it back in the box.

"I don't get it. Did someone get ahold of it somehow and try to kill him?"

"Dean tried to kill himself."

"No. I don't believe it. Why would he do that? The coins only make you kill someone you hate!"

"Dean hates himself more than anyone." Cas explained sadly.

Realization dawned on the younger hunter, and it hurt to see the heartbreak on his face. "I just thought he was drunk." Sam whispered. "I was angry with him. Those could have been the last words I said to him..."

Cas patted his back awkwardly. "But they weren't. He's okay now, he'll be fine."

"When will he wake up?" Sam hadn't taken his eyes off his brother's chest. Cas knew it was because he needed to see the rise and fall with each breath, reassure himself that Dean was alive.

"Soon. I healed him, but he will likely be in a weakened state for a day or two."

"Will he..." Sam swallowed hard. "He won't try again, will he? Now that the coin is put away?"

Cas hesitated. "The coin will no longer affect him."

"But?"

"The curse didn't create those suicidal feelings in your brother. It only intensified them. I don't know what his mental state will be like when he wakes."

Sam put his head in his hands. Why hadn't Dean told him any of this? He always seemed so self-assured. He had his moments, but didn't everyone?

But as Sam thought back, it became more clear. There had been so many warning signs.

 _"There ain't no me if there ain't no you."_

 _"I'm tired, Sam."_

 _"Can't you see? I'm poison. People get close to me, they get killed. Or worse."_

 _"You see a light at the end of this ugly-ass tunnel. I don't!"_

 _"I'm gonna die with a gun in my hand, cause it's the only thing I've got waiting for me."_

 _"I'm a grunt, Sam. You're not. You've always been the brains of this operation."_

The drinking. The nightmares. The bar fights.

Maybe Dean wasn't as okay as he pretended to be.

* * *

 **Let me just say that writing this chapter was hard. I looked for actual quotes from the show that were good examples of Dean's low self-esteem, possibly even suicidal thoughts. There were too damn many. Poor Dean :'(**


	4. Chapter 4

As Dean regained consciousness, he became aware of hushed voices. He opened his eyes to see Sam and Cas sitting on the bed across from him in the dim light. Sam's hair was still wet from the shower, and he looked pretty shaken up.

"Hello, Dean." Cas met his gaze.

Sam's head shot up, and he came to his brother's bedside. "Dean, how are you feeling?"

Dean sat up slowly. "I'm...not sure." He replied honestly. "What happened?"

"What do you remember?" Cas asked, standing behind Sam.

"Uhh...I took one of those damn coins, I thought it would help me find Crowley." He reached into his pocket, but it was gone.

"I returned it to its proper place, and took it to the storage unit where your father kept the other curse boxes." Cas explained.

"Oh."

"Do you remember...anything else?" Sam almost seemed afraid to ask.

"Yeah." Dean replied simply. He didn't really want to talk about it. He'd obviously survived the attempt, and the suicidal feeling had faded to its usual dull whisper in the back of his mind.

"Well, are you okay?"

"Yes, I'm fine, Sam." Dean snapped.

"I...hate to ask, but do we need to skip town? I found the...the empty pill bottles in the Impala." Sam swallowed hard, like it was physically painful to imagine Dean chugging them down. "You had to break into a pharmacy, right? Did anyone see you?"

"No. I had the common sense to black out the cameras first."

"Good."

"What you did was exceedingly stupid, Dean." Cas spoke up, frowning at him.

"Sorry," he mumbled.

"Those coins are dangerous. I told you how deadly they could be, and you took the chance anyway. You had to know that your self-hatred would surface."

Dean looked away. "I thought they just made you kill other people. I didn't realize it extended to..." He couldn't even say it.

"How are you really feeling?"

"I said I'm fine!" Dean immediately felt bad. Sam was just as traumatized as he was. "I'm okay, Sammy. Just tired. And really thirsty for some reason."

Sam went to the fridge and got him a bottle of water.

"Water, really? Toss me a beer, will ya?"

"Not happening." Sam glared.

"Fine," Dean rolled his eyes and took a drink. "How are you doing?"

"Me? You're the one that almost died."

"Yes, you, Sam. I remember...I mean, you were pretty freaked out."

"Damn right I was! You just...fell...and you had a seizure." Sam's voice broke. "You stopped breathing. I almost lost you. Cas barely got here in time."

"I'm sorry," Dean felt horrible. "It was just the curse, you know? I'd never leave you like that."

"I'm not so sure." Sam said quietly. "I mean, you're obviously not doing so hot if you hate yourself more than you hate Crowley."

Dean sighed. He recognized the look in Sam's eyes. It reminded him of when they were kids. Dean would come home all messed up from a hunt, and he'd put on a brave face for Sammy, who saw right through it.

"Cas, can you give us a minute?" He asked quietly.

The angel nodded. "Call if you need me." and he was gone.

Dean swung his legs over the edge of the bed and stood, regretting it instantly as a wave of dizziness swept over him and his legs refused to hold his weight.

"Woah, easy." Sam caught him. "Cas said you'd feel kinda weak for a couple days." He helped his brother back onto the bed.

"Ugh." Dean leaned back against the headboard until the lightheadedness passed. Sam sat next to him, that same worried expression clouding his eyes. "Alright, I know you're thinking it. Go ahead and ask." Dean grumbled.

"Cas told me those drugs were the exact combination needed to make sure you died fast. That no doctor would be able to save you in time. Dean, you were in and out of that pharmacy in ten minutes. Are we gonna talk about how you knew exactly what pills to take?"

"Lucky guess."

"That's bullshit. I think you know because you've thought about it before. Hell, you've _planned_ it before. That's why I can't let this go. You can't just say it was a one time thing, it was just the curse, and that it won't happen again. Because obviously you've been suicidal in the past."

Dean was quiet. He couldn't look his brother in the eyes.

"All I'm asking for is honesty, Dean. I'm worried about you."

"Okay, so this isn't the first time it's crossed my mind." Dean admitted.

"How do I know you won't try again?" Sam asked softly.

"Because every time I almost ended it, I stopped because of you. I can't do that to you, kid." Dean's voice broke. "You're still my pain-in-the-ass little brother, and it's my job to look out for you, okay Sammy?"

Sam nodded, not trusting his voice.

"I really am doing better," Dean reassured him. "Helping people makes it easier. Feels like I'm making a difference, you know?"

"Yeah," Sam cleared his throat and drew a shaky breath. "If it gets bad again, just promise you'll talk to me? Or Cas, or anybody."

"I promise." Dean wasn't sure he would actually follow through with that, but right now the important thing was comforting Sam.

"Thanks." Sam squeezed Dean's shoulder.

"Come here, kid." Dean sighed, pulling his brother into a hug.

"I thought you said no chick-flick moments," Sam mumbled.

"Shut up, Bitch." Dean grinned.

"Jerk." Sam could hear the smile in Dean's voice, and that was all he needed.

* * *

 **Hey guys :) Do you think I should add another chapter, or should I leave it here? If I do write another chapter, what would you want to see happen? Thanks so much to everyone who's reviewed! It really helps motivate me.**


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